Milan have undergone three different owners in recent years.
Calabria said, “We have grown together in recent years. It has been a long and difficult journey. The last few years have been difficult for everyone.
“There have been several owners, for us players it has not been easy. To be great again, you need a solid club."
However, Calabria praised technical director Paolo Maldini for his work.
“He's the captain of the Milan captains," Calabria continued. “He's the man who best represents Milan.
“He's not one of many words, but he always spurs you on and his presence alone makes you believe in the project.
“His presence helped the rebirth of Milan."